Summary

At the height of the Cold War between the United States and the Soviet Union, Mark Bragg, an officer in the Air Force, warns his brother Randy that nuclear war is imminent. Mark, who lives in Omaha, sends his wife, Helen, and his children, Ben Franklin and Peyton, to live with Randy in the isolated Florida town of Fort Repose. While he waits for them to arrive, Randy warns his friends, including his neighbors, the Henrys, and his girlfriend, Lib McGovern. He begins to stockpile food, and picks up Helen and her children at the airport, as the radio reports that tensions are escalating between the two superpowers. The next morning, war breaks out, and nuclear weapons destroy all of Florida's major cities. Washington is also destroyed, and a low-level Cabinet official becomes President. Having lost all power and communication with the rest of the country, Fort Repose is completely isolated.

Disorder prevails in the small town. Randy's best friend, the local doctor Dan Gunn is beaten up by drug addicts, who ransack his clinic; the local police chief is killed; the bank president, Edgar Quisenberry, kills himself. But Randy and his friends, who all eventually come to live with him in his house on River Road, manage to survive and maintain a kind of order in their lives. Randy hooks up a supply of fresh water for his house and his neighbors, and the Henry farm provides food, as does the nearby river. Dan continues to travel around the town seeing patients, doing the best he can with limited medical supplies. A crisis occurs when he discovers that a number of people are suffering from radiation poisoning, acquired from irradiated jewelry that a man named Porky Logan brought back from near a contaminated city. Dan and Randy handle the crisis together. They collect the jewelry and bury it, along with Porky Logan's body, in a lead-lined coffin. When the townsfolk refuse to help bury the coffin, Randy brandishes a gun and forces them to do so.

Randy's authority in the town becomes more and more respected. A radio announcement declares that former Army Reserve officers are to assume responsibility for martial law in isolated areas, and Randy is a former Reserve officer, so he begins to post decrees and take responsibility for law enforcement. When a group of bandits attack and brutally beat Dan Gunn, he collects a posse and hunts them down — on the same afternoon that he and Lib are married. He and his friend kill three of the bandits and hang the other, although his neighbor, Malachai Henry, is shot and dies.

The town struggles through the summer, surviving a brief shortage of fish, and Randy solves a crisis involving a lack of salt. He combs the diary kept by his ancestor, who founded the town, and finds a reference to a nearby pool with a plentiful supply of salt. In autumn, government planes begin flying over the town, and a helicopter lands, carrying Paul Hart, a military man and friend of Randy's from before the war. He tells them that the country is still trying to restore basic services, and that centuries may pass before the contaminated regions become clean. He also confirms that Mark died in the war, meaning that Helen is free to marry Dan, with whom she has fallen in love. He offers to take them out of Fort Repose, but they all prefer to remain in the community they have rebuilt.